Major Work Activity B - Services, diagnoses and repairs engines and supporting systems

Table of Contents

• Task B-5 Services, diagnoses and repairs base engines
  • B-5.01 Services base engines
  • B-5.02 Diagnoses base engines
  • B-5.03 Repairs base engines
• Task B-6 Services, diagnoses and repairs lubrication systems
  • B-6.01 Services lubrication systems
  • B-6.02 Diagnoses lubrication systems
  • B-6.03 Repairs lubrication systems
• Task B-7 Services, diagnoses and repairs intake systems
  • B-7.01 Services intake systems
  • B-7.02 Diagnoses intake systems
  • B-7.03 Repairs intake systems
• Task B-8 Services, diagnoses and repairs exhaust systems
  • B-8.01 Services exhaust systems
  • B-8.02 Diagnoses exhaust systems
  • B-8.03 Repairs exhaust systems
• Task B-9 Services, diagnoses and repairs engine management systems
  • B-9.01 Services engine management systems
  • B-9.02 Diagnoses engine management systems
  • B-9.03 Repairs engine management systems
• Task B-10 Services, diagnoses and repairs fuel delivery systems
  • B-10.01 Services fuel delivery systems
  • B-10.02 Diagnoses fuel delivery systems
  • B-10.03 Repairs fuel delivery systems
• Task B-11 Services, diagnoses and repairs engine retarder systems
  • B-11.01 Services engine retarder systems
  • B-11.02 Diagnoses engine retarder systems
  • B-11.03 Repairs engine retarder systems
• Task B-12 Services, diagnoses and repairs cooling systems
  • B-12.01 Services cooling systems
  • B-12.02 Diagnoses cooling systems
  • B-12.03 Repairs cooling systems

Task B-5 Services, diagnoses and repairs base engines

Task Descriptor

The engine produces power through engine speed and torque to enable movement of the vehicle. Servicing includes the adjustment of components as well as their routine maintenance. Diagnosing is required to locate failures in order to effectively perform repairs on the engine, which may include replacement or rebuilding of components.

Truck and transport mechanics service, diagnose and repair the base engine and its components to ensure proper engine function and reduce down time.

Range of Variables

• manufacturers’ service information include: maintenance schedule, specifications, recommendations, procedures, standards
• components include: blocks, crankshafts, camshafts, cylinder heads, pistons, bushings, rocker arms, gears, bearings

Range of Variables

• components include: blocks, crankshafts, camshafts, cylinder heads, pistons, bushings, rocker arms, gears, bearings
• manufacturers’ service information include: maintenance schedule, specifications, recommendations, procedures, standards
• hazards include: sharp edges, weight, size, heat, moving parts

Range of Variables

• symptoms of problems include:abnormal vibration,leaks, noises, no start, hard start, low power, low oil pressure
• tools and equipment include: temperature measuring devices, compression testers, wear measuring instruments, pressure measuring devices, dynamometers, fluid analysis sampling devices, electronic service tools
• manufacturers’ service information include: maintenance schedule, specifications, recommendations, procedures, standards
• sensory inspections include: feeling for vibrations, listening for abnormal sounds, smelling for burning oil
• tests include:compression tests, cylinder leakage, oil pressure, dynamometer checks, fluid sampling for analysis, injector cut-out
• components include: valves, pistons, blocks, liners, cylinder heads, cam shafts, valve trains, crank shafts, connecting rods, gears, bearings, seals, sealants, gaskets
• next steps include: repairs, component replacement, further diagnosis

Range of Variables

• components include: valves, pistons, blocks, liners, cylinder heads, cam shafts, valve trains, crank shafts, connecting rods, gears, bearings, seals, sealants, gaskets
• manufacturers’ service information include: maintenance schedule, specifications, recommendations, procedures, standards
• tools and equipment include: temperature measuring devices, compression testers, wear measuring instruments, pressure measuring devices, dynamometers, fluid analysis sampling devices, electronic service tools
• hazards include: sharp edges, weight, size, heat, moving parts
• symptoms of problems include:abnormal vibration,leaks, noises, no start, hard start, low power, low oil pressure

Range of Variables

• tools and equipment include: torque wrenches, dial indicators, measuring instruments, lifting devices, engine rotator, torque-to-yield gauge, feeler gauges, dynamometer, electronic service tools
• manufacturers’ service information include: maintenance schedule, specifications, recommendations, procedures, standards
• functions include: disconnecting electrical connections, draining fluids, steam cleaning engine
• components include: valves, pistons, piston rings, blocks, liners, cylinder heads, cam shafts, valve trains, crank shafts, connecting rods, timing gears, bearings, seals, sealants, gaskets
• cylinder head components include: valves, seals, valve guides, valve seats, springs, injector sleeves/cups
• methods (to repair base engine) include: replacing parts causing failure, grinding valves, cutting block counterbores and shimming cylinder liners, using oversized bearings
• adjustments include: adjusting valve train clearances, setting timing gears
• methods (to verify repairs) include: road testing, dynamometer testing, electronic diagnostic testing

Range of Variables

• components include: valves, pistons, piston rings, blocks, liners, cylinder heads, cam shafts, valve trains, crank shafts, connecting rods, timing gears, bearings, seals, sealants, gaskets
• tools and equipment include: torque wrenches, dial indicators, measuring instruments, lifting devices, engine rotator, torque-to-yield gauge, feeler gauges, dynamometer, electronic service tools
• hazards include: sharp edges, weight, size, heat, moving parts

Task B-6 Services, diagnoses and repairs lubrication systems

Task Descriptor

The lubrication system regulates the flow of oil throughout the engine and its components to the oil cooler to transfer heat from the oil to the cooling system. It also flushes contaminants away from engine components through the oil filter. Its main purpose is to protect internal engine components by creating a thin film of oil between metal surfaces.

Servicing includes the replacement of consumables as well as the routine maintenance of the system. Diagnosing is required to determine the root cause of failures in order to effectively perform repairs on lubrication system.

Truck and transport mechanics service, diagnose and repair lubrication systems to ensure proper protection of the engine and its components.

Range of Variables

• manufacturers’ service information include: maintenance schedule, specifications, recommendations, procedures, standards
• components include: oil pump, oil cooler, pressure regulator valves, bypass valves, inlet strainers, oil filters
• sensory inspections include: looking for leaks, smelling for burnt oil, checking magnetic drain plug for contamination
• consumables include: oil filters, oil

Range of Variables

• components include: oil pump, oil cooler, pressure regulator valves, bypass valves, inlet strainers, oil filters
• consumables include: oil filters, oil
• manufacturers’ service information include: maintenance schedule, specifications, recommendations, procedures, standards
• fluid classifications include:viscosity, American Petroleum Institute (API), Society of Automotive Engineers (SAE)
• hazards include: high temperatures, skin irritation, splashing/dripping oil, fire

Range of Variables

• symptoms of problems include: low or high fluid level, low or high oil pressure, external oil leaks, oil dilution, cross-contaminated oil, high oil temperature
• tools and equipment include: pressure gauges, infrared/direct contact thermometers, dyes, fluid analysis sampling devices
• manufacturers’ service information include: maintenance schedule, specifications, recommendations, procedures, standards
• sensory inspections include: listening for engine knock, smelling oil, looking for leaks, visual inspection of levels
• tests include: oil pressure and temperature, contamination
• next steps include: repairs, component replacement or adjustment, further diagnosis

Range of Variables

• components include: oil pump, oil cooler, pressure regulator valves, bypass valves, inlet strainers, oil filters
• manufacturers’ service information include: maintenance schedule, specifications, recommendations, procedures, standards
• tools and equipment include: pressure gauges, infrared/direct contact thermometers, dyes, fluid analysis sampling devices
• hazards include: high temperatures, skin irritation, splashing/dripping oil, fire
• symptoms of problems include: low or high fluid level, low or high oil pressure, external oil leaks, oil dilution, cross-contaminated oil, high oil temperature

Range of Variables

• manufacturers’ service information include: maintenance schedule, specifications, recommendations, procedures, standards
• components include: pumps, oil thermostats, piston cooling nozzles, bearings
• methods include: checking oil pressure, temperature and levels

Range of Variables

• components include: pumps, oil thermostats, piston cooling nozzles, bearings
• manufacturers’ service information include: maintenance schedule, specifications, recommendations, procedures, standards
• hazards include: high temperatures, skin irritation, splashing/dripping oil, fire

Task B-7 Services, diagnoses and repairs intake systems

Task Descriptor

The engine intake systems supply cool filtered air to the engine. Emissions control systems are often an integral part of intake systems.

Servicing includes the replacement of consumables and components as well as their routine maintenance. Diagnosing is required to determine root cause of failures in order to effectively perform repairs on intake systems.

Truck and transport mechanics must service, diagnose and repair intake systems to ensure proper operation and performance of the engine.

Range of Variables

• manufacturers’ service information include: maintenance schedule, specifications, recommendations, procedures, standards
• sensory inspections include: looking for soot deposits indicating leaks, listening for air escaping, looking for incorrect fit or installation of piping, checking gauges
• components include: charge air coolers (CAC), turbochargers (variable geometry turbochargers [VGT] and compound), piping, manifolds, gaskets, filter housing, clamps, pressure and temperature sensors, intake throttle valves
• consumables include: gaskets, filters

Range of Variables

• components include: charge air coolers (CAC), turbochargers (variable geometry turbochargers [VGT] and compound), piping, manifolds, gaskets, filter housing, clamps, pressure and temperature sensors, intake throttle valves
• consumables include: gaskets, filters
• manufacturers’ service information include: maintenance schedule, specifications, recommendations, procedures, standards
• starting aids include: pre-heaters, ether injection
• hazards include: running engine in confined spaces, dangers surrounding air inlets

Range of Variables

• symptoms of problems include: visible exhaust smoke, low power, no start, low boost, noises
• tools and equipment include: electronic service tools, intake CAC pressure test kits, manometers
• manufacturers’ service information include: maintenance schedule, specifications, recommendations, procedures, standards
• sensory inspections include: looking for soot deposits indicating leaks, listening for air escaping, looking for incorrect fit or installation of piping, checking gauges
• tests include: boost test, intake and CAC pressure test, exhaust gas recirculation (EGR) operation test
• next steps include: repairs, component replacement or adjustment, further diagnosis
• starting aids include: pre-heaters, ether injection

Range of Variables

• components include: CAC, turbochargers (VGT and compound), piping, manifolds, gaskets, filter housing, clamps, pressure and temperature sensors, intake throttle valve
• consumables include: gaskets, filters
• manufacturers’ service information include: maintenance schedule, specifications, recommendations, procedures, standards
• starting aids include: pre-heaters, ether injection
• intake system contamination includes: dust, oil, antifreeze
• emergency shutdown devices include: air dams (cable and switch operated)
• tools and equipment include: electronic service tools, intake CAC pressure test kits, manometers
• hazards include: running engine in confined spaces, dangers surrounding air inlets
• symptoms of problems include: visible exhaust smoke, low power, no start, low boost, noises

Range of Variables

• manufacturers’ service information include: maintenance schedule, specifications, recommendations, procedures, standards
• components include: CAC, turbochargers (VGT and compound), piping, manifolds, gaskets, filter housing, clamps, pressure and temperature sensors, intake throttle valves
• electronic components include: intake throttle valves, VGT, EGR
• methods include: pressure testing intake system, performing sensory observations of intake system

Range of Variables

• components include: CAC, turbochargers (VGT and compound), piping, manifolds, gaskets, filter housing, clamps, pressure and temperature sensors, intake throttle valves
• consumables include: gaskets, filters
• manufacturers’ service information include: maintenance schedule, specifications, recommendations, procedures, standards
• hazards include: running engine in confined spaces, dangers surrounding air inlets

Task B-8 Services, diagnoses and repairs exhaust systems

Task Descriptor

Exhaust systems work in conjunction with other engine systems to reduce noise pollution, nitric oxide and nitrogen dioxide (NOx gases), carbon emissions and other harmful by-products of combustion to meet jurisdictional environmental requirements.

Servicing includes the replacement of consumables and components as well as their routine maintenance. Diagnosing is required to determine root cause of failures in order to effectively perform repairs on exhaust systems.

Truck and transport mechanics service, diagnose and repair exhaust systems to ensure proper operation and performance of the engine, and to ensure emissions levels meet requirements.

Range of Variables

• tools and equipment include: electronic service tools, temperature and pressure measuring devices, diesel exhaust fluid (DEF) refractometer, diesel particulate filter (DPF) cleaning machines
• manufacturers’ service information include: maintenance schedule, specifications, recommendations, procedures, standards
• components include: DPFs, fluid dosing pump, pressure differential and temperature sensors, DEF injectors, catalysts, EGR valves and coolers, turbochargers (VGT and compound), exhaust manifolds
• sensory inspections include: looking for leaks, observing DEF levels, looking for accumulation of urea crystals, looking for visible exhaust smoke
• consumables include: DEF, filters

Range of Variables

• components include: DPFs, fluid dosing pump, pressure differential and temperature sensors, DEF injectors, catalysts, EGR valves and coolers, turbochargers (VGT and compound), exhaust manifolds
• consumables include: DEF, filters
• types of emission systems include: DPF, EGR, selective catalytic reduction (SCR), crankcase ventilation systems
• manufacturers’ service information include: maintenance schedule, specifications, recommendations, procedures, standards
• types of controls include: electronic control management systems, electronic and manual switches
• tools and equipment include: electronic service tools, temperature and pressure measuring devices, DEF refractometer, DPF cleaning machines
• hazards include: skin and eye irritation, high temperature, hazardous fumes, operating engine in confined spaces

Range of Variables

• symptoms of problems include: leaks, low power, visible exhaust smoke, frequent regeneration, warning lights, fault codes
• tools and equipment include: electronic service tools, temperature and pressure measuring devices
• manufacturers’ service information include: maintenance schedule, specifications, recommendations, procedures, standards
• sensory inspections include: looking for leaks, observing DEF levels, looking for accumulation of urea crystals, looking for visible exhaust smoke
• tests include: computer-based tests, DEF concentration tests, manual temperature and pressure gauge tests
• next steps include: repairs, component replacement or adjustment, further diagnosis

Range of Variables

• components include: DPFs, fluid dosing pump, pressure differential and temperature sensors, DEF injectors, catalysts, EGR valves and coolers, turbochargers (VGT and compound), exhaust manifolds
• consumables include: DEF, filters
• manufacturers’ service information include: maintenance schedule, specifications, recommendations, procedures, standards
• types of emission systems include: DPF, EGR, SCR, crankcase ventilation systems
• types of controls include: electronic control management systems, electronic and manual switches
• tools and equipment include: electronic service tools, temperature and pressure measuring devices
• hazards include: skin and eye irritation, high temperature, hazardous fumes, operating engine in confined spaces, noises
• symptoms of problems include: leaks, low power, visible exhaust smoke, frequent regeneration, warning lights, fault codes

Range of Variables

• tools and equipment include: DPF cleaning units, manufacturer-specific tools, welding equipment, electronic service tools, temperature and pressure measuring devices
• manufacturers’ service information include: maintenance schedule, specifications, recommendations, procedures, standards
• components include: DPFs, fluid dosing pump, pressure differential and temperature sensors, DEF injectors, catalysts, EGR valves and coolers, turbochargers (VGT and compound), exhaust manifolds
• methods include: operating vehicle, parked regeneration, monitoring operation

Range of Variables

• components include: DPFs, fluid dosing pump, pressure differential and temperature sensors, DEF injectors, catalysts, EGR valves and coolers, turbochargers (VGT and compound), exhaust manifolds
• consumables include: DEF, filters
• manufacturers’ service information include: maintenance schedule, specifications, recommendations, procedures, standards
• types of emission systems include: DPF, EGR, SCR, crankcase ventilation systems
• types of controls include: electronic control management systems, electronic and manual switches
• tools and equipment include: DPF cleaning units, manufacturer-specific tools, welding equipment, electronic service tools, temperature and pressure measuring devices
• hazards include: skin and eye irritation, high temperature, hazardous fumes, operating engine in confined spaces

Task B-9 Services, diagnoses and repairs engine management systems

Task Descriptor

Engine management systems receive analog/digital inputs and distribute analog/digital outputs to many components throughout the vehicle to optimize vehicle performance.

Servicing is primarily a matter of updating software to meet both manufacturer programming and fleet/owner requirements. Diagnosing is required to determine root cause of failures in order to effectively perform repairs on engine management systems.

Truck and transport mechanics service, diagnose and repair engine management systems to ensure proper operation of multiple components of the vehicle.

Range of Variables

• tools and equipment include: electronic service tools, multimeters, breakout harnesses
• manufacturers’ service information include: maintenance schedule, specifications, recommendations, procedures, standards
• ECM parameters include: shutdowns, cruise controls, speed controls, fan controls, application specific (e.g., enabling PTO, geo-fencing, retarder, shift points)

Range of Variables

• components include: harnesses, ECMs, switches, sensors, actuators
• tools and equipment include: electronic service tools, multimeters, breakout harnesses

Range of Variables

• symptoms of problems include: misfires, gauges with readings outside expected range, engine shutdowns, no start, de-rated power, fault codes, warning lights
• tools and equipment include: electronic service tools, multimeters, pin-out equipment, break-out harnesses
• manufacturers’ service information include: maintenance schedule, specifications, recommendations, procedures, standards
• failures include: poor connections, chafed or corroded harnesses, faulty components
• tests include: resistance, voltage drop, commanded actuator
• next steps include: repairs, component replacement or adjustment, further diagnosis

Range of Variables

• components include: harnesses, ECMs, switches, sensors, actuators
• manufacturers’ service information include: maintenance schedule, specifications, recommendations, procedures, standards
• types of specialized connectors and harnesses include: sensor connections, injector harnesses, ECM connectors
• tools and equipment include: electronic service tools, multimeters, pin-out equipment, break-out harnesses
• hazards include: high-voltage outputs, hot surfaces, sharp edges, pinch/crush points, moving parts
• symptoms of problems include: misfires, gauges with readings outside expected range, engine shutdowns, no start, de-rated power, fault codes, warning lights
• failures include: poor connections, chafed or corroded harnesses, faulty components

Range of Variables

• manufacturers’ service information include: maintenance schedule, specifications, recommendations, procedures, standards
• components include: ECMs, harnesses, sensors, actuators, resistors, switches
• components (to be repaired) include: harnesses, connectors, terminals
• components (to be calibrated) include: injectors, turbochargers, speed control sensors, EGR valves, intake throttle valves, exhaust sensors
• methods include: clearing codes, resetting virtual breaker, verifying that fault codes remain inactive, performing operational tests

Range of Variables

• components include: ECMs, harnesses, sensors, actuators, resistors, switches
• intake throttle valves, exhaust sensors
• hazards include: high-voltage outputs, hot surfaces, sharp edges, pinch/crush points, moving parts

Task B-10 Services, diagnoses and repairs fuel delivery systems

Task Descriptor

The fuel delivery system supplies clean fuel to the engine at regulated pressure and volume. Fuels include diesel, propane, bio-diesel and natural gas.

Truck and transport mechanics service, diagnose and repair fuel delivery systems to ensure proper engine operation and minimize downtime.

Range of Variables

• manufacturers’ service information include: maintenance schedule, specifications, recommendations, procedures, standards
• sensory inspections include: smelling or looking for fuel leaks, looking for excessive exhaust smoke, listening for engine miss
• components include: pumps, injectors, tanks, check valves, fuel regulating valves, lines
• consumables include: fuels, filters, fuel-water separators, fuel additives

Range of Variables

• components include: pumps, injectors, tanks, check valves, fuel regulating valves, lines
• consumables include: fuels, filters, fuel-water separators, fuel additives
• types of fuel delivery systems include: mechanical, electronic
• types of fuels include: winter and summer fuels, natural gas, propane, diesel, biodiesel, gasoline
• types of fuel additives include: cetane boost, antigel/antiwax, fuel conditioner
• manufacturers’ service information include: maintenance schedule, specifications, recommendations, procedures, standards
• hazards include: extreme high pressure, flammable and explosive materials, environmental irritant, noxious fumes

Range of Variables

• symptoms of problems include:exhaust smoke, rough running engine, poor engine performance, no start, fuel leaks
• tools and equipment include: pressure gauges, vacuum gauges, flow meters, dynamometers, electronic service tools, injector testers
• manufacturers’ service information include: maintenance schedule, specifications, recommendations, procedures, standards
• sensory inspections include: smelling and looking for leaks, listening for engine misfires and vibrations, looking for excessive exhaust smoke
• tests include: injector cut-out, injector performance, transfer pump pressure, return volume, filter restriction, injector leakage
• next steps include: repairs, component replacement or adjustment, further diagnosis

Range of Variables

• components include: pumps, injectors, tanks, check valves, fuel regulating valves, lines
• consumables include: fuels, filters, fuel-water separators
• types of fuel delivery systems include: mechanical, electronic
• manufacturers’ service information include: maintenance schedule, specifications, recommendations, procedures, standards
• types of fuels include: winter and summer fuels, natural gas, propane, diesel, biodiesel, gasoline
• types of fuel additives include: cetane boost, antigel/antiwax, fuel conditioners
• tools and equipment include: pressure gauges, vacuum gauges, flow meters, dynamometers, electronic service tools, injector testers
• hazards include: extreme high pressure, flammable and explosive materials, environmental irritant, noxious fumes
• symptoms of problems include:exhaust smoke, rough running engine, poor engine performance, no start, fuel leaks

Range of Variables

• tools and equipment include: torque wrenches, manufacturer-specific tools, pullers, dial indicators, electronic service tools
• manufacturers’ service information include: maintenance schedule, specifications, recommendations, procedures, standards
• components include: low- and high-pressure pumps, injectors, tanks, check valves, fuel regulating valves, lines
• measurements include: injector height, fuel pressure, pump inlet restriction
• adjustments include: entering calibration values for electronic injectors, setting injector pre‑load, confirming high and low throttle (mechanical injection systems), adjusting throttle linkages, setting injector height, setting pump timing
• methods include: running equipment at operating condition, performing manufacturers’ test procedures

Range of Variables

• components include: low- and high-pressure pumps, injectors, tanks, check valves, fuel regulating valves, lines
• consumables include: fuels, filters, fuel-water separators
• types of fuel delivery systems include: mechanical, electronic
• types of fuels include: winter and summer fuels, natural gas, propane, diesel, biodiesel, gasoline
• tools and equipment include: torque wrenches, manufacturer-specific tools, pullers, dial indicators, electronic service tools
• hazards include: extreme high pressure, flammable and explosive materials, environmental irritant, noxious fumes

Task B-11 Services, diagnoses and repairs engine retarder systems

Task Descriptor

Engine retarder systems are an optional component used to assist the primary braking system to slow the vehicle and to prolong primary brake life. These systems receive inputs from the vehicle and operator to determine appropriate timing to manage compression within the engine by controlling exhaust flow or valve position.

Truck and transport mechanics service, diagnose and repair engine retarder systems to ensure proper function and reduce down time.

Range of Variables

• tools and equipment include: manufacturer-specific gauges, feeler gauge
• manufacturers’ service information include: maintenance schedule, specifications, recommendations, procedures, standards
• adjustments include: valve clearances, parameters, compression brake clearances

Range of Variables

• types of engine retarder systems include: compression, exhaust
• components include: harnesses, exhaust valves, secondary pistons, ECMs, solenoids, switches, O-rings
• tools and equipment include: manufacturer-specific gauges, feeler gauge
• hazards include: high temperatures, skin irritation, moving parts, sharp edges

Range of Variables

• symptoms of problems include: poor engine retarder performance,unusual engine noises, loss of oil pressure
• tools and equipment include:electronic service tools, pressure testing equipment, multimeters, feeler gauges
• manufacturers’ service information include: maintenance schedule, specifications, recommendations, procedures, standards
• tests include: oil pressure, solenoid operation, electrical circuitry, functionality
• next steps include: repairs, component replacement or adjustment, further diagnosis

Range of Variables

• components include: harnesses, exhaust valves, secondary pistons, ECMs, solenoids, switches
• types of engine retarder systems include: compression, exhaust
• manufacturers’ service information include: maintenance schedule, specifications, recommendations, procedures, standards
• tools and equipment include:electronic service tools, pressure testing equipment, multimeters, feeler gauges
• hazards include: high temperatures, skin irritation, moving parts, sharp edges
• symptoms of problems include: poor engine retarder performance,unusual engine noises, loss of oil pressure

Range of Variables

• tools and equipment include:electronic service tools, pressure testing equipment, multimeter, feeler gauges, manufacturer-specific tools
• manufacturers’ service information include: maintenance schedule, specifications, recommendations, procedures, standards
• components include: harnesses, exhaust valves, secondary pistons, ECMs, solenoids, switches
• adjustments include: valve clearances, parameters, exhaust brake, compression brake clearances
• methods include: road testing, function testing

Range of Variables

• components include: harnesses, exhaust valves, secondary pistons, ECMs, solenoids, switches
• types of engine retarder systems include: compression, exhaust
• tools and equipment include:electronic service tools, pressure testing equipment, multimeter, feeler gauges, manufacturer-specific tools
• hazards include: high temperatures, skin irritation, moving parts, sharp edges

Task B-12 Services, diagnoses and repairs cooling systems

Task Descriptor

The cooling system regulates the circulation of coolant throughout the engine and other components to the radiator to transfer heat from the engine to the atmosphere and the heating, ventilation and air conditioning (HVAC) system.

Servicing includes the replacement of consumables and components as well as their routine maintenance. Diagnosing is required to determine root cause of failures in order to effectively perform repairs on cooling systems.

Truck and transport mechanics service, diagnose and repair cooling systems to ensure proper operating temperature of the engine and function of the HVAC system.

Range of Variables

• tools and equipment include: refractometers, test strips, hydrometers, vacuum fill kits, flushing equipment
• manufacturers’ service information include: maintenance schedule, specifications, recommendations, procedures, standards
• sensory inspections include: smelling leaking coolant, looking for leaks
• problems include: coolant leaks, low levels, condition of coolant, deterioration and contamination, cracked or missing fan blades, damaged hoses and belts, white exhaust
• stored energy includes: heat, pressure
• consumables include: coolant filters, coolant

Range of Variables

• components include: oil cooler, thermostats, cooling fan, radiator, hoses, clamps, seals, sealants, gaskets, fans, fan drives, radiator shrouds, belts, radiator caps, recovery tanks, coolant heaters, sensors, mechanical and electric water pumps, controllers
• consumables include: coolant filters, coolant
• types of coolants include: conventional, extended life, diesel specific, waterless
• coolant properties include: pH, freezing point, additive concentrations, conductivity
• tools and equipment include: refractometers, test strips, hydrometers, vacuum fill kits, flushing equipment
• hazards include: pressure, steam, extreme heat, moving parts, skin irritation, toxicity
• stored energy includes: heat, pressure

Range of Variables

• symptoms of problems include: coolant loss, low or high operating temperatures, excessive system pressure, warning lights, coolant leaks, no cab heat
• tools and equipment include:leak testing equipment, pressure measuring devices, refractometers, temperature measuring devices, test strips, fluid analysis sampling kit, hydrometers, belt tension gauges, electronic service tools
• manufacturers’ service information include: maintenance schedule, specifications, recommendations, procedures, standards
• sensory inspections include: looking for leaks and cracked hoses, smelling for coolant, feeling hoses for damage, checking for contact wear (improper length, routing and securing of hose)
• tests include: dye, pressure, temperature, fan speed, radiator cap
• system functions include: correct operation of thermostat, water pump, fan hub and radiator cap
• next steps include: repairs, component replacement or adjustment, further diagnosis

Range of Variables

• components include: oil cooler, thermostats, cooling fan, radiator, hoses, clamps, seals, sealants, gaskets, fans, fan drives, radiator shrouds, belts, radiator caps, recovery tanks, coolant heaters, sensors, mechanical and electric water pumps, controllers
• manufacturers’ service information include: maintenance schedule, specifications, recommendations, procedures, standards
• types of coolants include: conventional, extended life, diesel specific, waterless
• coolant properties include: pH, freezing point, additive concentrations, conductivity
• tools and equipment include:leak testing equipment, pressure measuring devices, refractometers, temperature measuring devices, test strips, fluid analysis sampling kit, hydrometers, belt tension gauges, electronic service tools
• hazards include: pressure, steam, extreme heat, moving parts, skin irritation, toxicity
• symptoms of problems include: coolant loss, low or high operating temperatures, excessive system pressure, warning lights, coolant leaks, no cab heat

Range of Variables

• tools and equipment include: torque wrenches, manufacturer-specific tools, lifting devices, flushing equipment, coolant handling equipment, temperature measuring devices, thermostat testing equipment
• manufacturers’ service information include: maintenance schedule, specifications, recommendations, procedures, standards
• components include: oil cooler, thermostats, cooling fan, radiator, hoses, clamps, seals, sealants, gaskets, fans, fan drives, radiator shrouds, belts, radiator caps, recovery tanks, coolant heaters, sensors, mechanical and electric water pumps, controllers
• methods include: road testing, pressure testing

Range of Variables

• components include: oil cooler, thermostats, cooling fan, radiator, hoses, clamps, seals, sealants, gaskets, fans, fan drives, radiator shrouds, belts, radiator caps, recovery tanks, coolant heaters, sensors, mechanical and electric water pumps, controllers
• types of coolants include: conventional, extended life, diesel specific, waterless
• coolant properties include: pH, freezing point, additive concentrations, conductivity
• tools and equipment include: torque wrenches, manufacturer-specific tools, lifting devices, flushing equipment, coolant handling equipment, temperature measuring devices, thermostat testing equipment
• hazards include: pressure, steam, extreme heat, moving parts, skin irritation, toxicity

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